The invention relates in general to a thermal energy machine (“TEM”), and in particular to a single station or a multiple station thermal energy machine with interchangeable components for processing different sized parts with a single frame weldment.
TEM was introduced in the late 1960's as an effective way to remove internal and external burrs and flashing from machined or molded metal and plastic parts. TEM is also known “gas detonation deburring,” “thermal deburring,” “combustion chamber treatment,” and “rapid high energy removal of superfluous projections.” The concept behind TEM is elegantly simple: instead of mechanically abrading off burrs and flashing, the burrs and flashing are simply burned away in a fraction of a second. This simple concept is applied in an exciting way: one or more metal or plastic parts requiring deburring or deflashing are sealed inside a combustion chamber and surrounded with a highly pressurized explosive gas mixture which is then ignited by an electric spark. The resulting explosion produces a thermal shock wave that literally burns away (oxidizes) the burrs and flashings from the parts while the relatively great thermal mass of the parts prevents the parts themselves from being damaged by the thermal shock wave. The explosive flame temperature can reach over 6,000° F. (3,316° C.). The explosion lasts only milliseconds and the entire load-to-load cycle time is on the order of half a minute.
A conventional C-frame TEM machine 100 for thermal deburring of parts is shown in FIGS. 7, 8 and 9. The TEM machine comprises a stationary frame 101 in which is rigidly secured a working chamber 102 having an admission valve 103, a spark plug 104 and a discharge valve 105 incorporated in its wall. The chamber 102 is in the form of a cylinder open at both ends, the lower hole of the chamber 102 (as shown in the drawings) is a loading hole. The frame 101 also supports a pneumatic cylinder 106 having a movable member thereof carrying a bottom member 107, which is designed for closing and opening the chamber 102 and which comprises a hollow cylinder having end plates and openings 108 in the peripheral wall, the height and outside diameter of the cylinder being about equal to the height and inside diameter of the working chamber 102. The inner surface of the lower end plate of the bottom member 107 (as shown in the drawings) functions as a worktable 109 for supporting a part 110 being treated which are installed and removed through the openings 108. The bottom member 107 is mounted for movement along the axis of the chamber 102. An elastic sealing ring 111 is installed between the chamber 102 and bottom member 107 on the side of the loading hole of the chamber 102 and an auxiliary sealing ring 112 is provided on the side opposite to the loading hole. The sealing rings 111 and 112 may be made of any appropriate sealing materials, e.g. of rubber of PTFE.
In the initial position, the bottom member 107 (FIGS. 7, 8 and 9) is lowered as shown in FIG. 8. A part 110 that is to be treated (or a plurality of parts to be treated) is placed through the opening 108 onto the worktable 109. Then, the bottom member 107 supporting the part 110 is raised by the pneumatic cylinder 106 along the inner wall of the working chamber 102 to the upper position as shown in FIG. 7. The elastic sealing rings 111 and 112 will thus seal the interior space of the working chamber 102. After the chamber 102 has been sealed, a fuel mixture is admitted to its interior space through the openings 108 and admission valve 103, and the fuel mixture is ignited by the spark plug 104. As a result of a rapid temperature and pressure rise in the interior space of the working chamber 102, burs of the parts 110 being treated are burnt and/or fused owing to their large surface and relatively small mass.
After the discharge valve 105 is opened, combustion products are discharged from the interior space of the working chamber 102, and the bottom member 107 is lowered by the pneumatic cylinder 106 to take the initial position. After the part 110 being treated has been removed from the interior space of the working chamber 102 and a next part 110 has been placed in the worktable 109, the working cycle is repeated.
The conventional TEM machine described above has a number of drawbacks. Most importantly, the single size of the chamber and the single stroke length of the pneumatic cylinder limit the size and number of parts that can be placed in the chamber. In addition, the amount of the gas mixture that may be used in the TEM process for a part may become excessive, especially for a small part, which increases the overall operational costs of TEM machine. Therefore, it would be desirable to provide a TEM machine that has a selectively adjustable chamber size and pneumatic cylinder stroke length to accommodate parts of different sizes.